Granted Patent
Utility
US 4,579,376 · App. 06/589,453
Fail-secure and fail-safe door lock mechanism
Inventor:
Newton W. Charlton
Patented Case
View Patent ↗
Granted: Apr 1, 1986
Filed: Mar 14, 1984
Inventor
Newton W. Charlton
Assignee (at issue)
Security Engineering, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.